Isolate tests a bit more

This patch isolates mongodb tests and adds new `shortcut-methods` to
base clases in order to make it easier for subclasses to access conf
instances, override them or even hook them.

Change-Id: I8fe05bf383198244616499adb60480859f1ec7c6
Revert "Support building wheels (PEP-427)"

Universal means support for py2/py3. 

Marconi doesn't support PY3K

This reverts commit 4d6830104dfe7a1b728b8782a02af5b99ca0366f
Merge "Revert "Support building wheels (PEP-427)""